Not to sound mean to this topic, but it has practically been covered in the below link:
If you want my honest opinion on the matter however, I can provide it. To become a Trusted member has one main aspect which you MUST apply to even gain a chance at this goal; that aspect is time. You must wait for the Operators to judge you, and then take you into consideration.
The second aspect that the Operators look for is if the player is active. What I mean by this is that if you are active on the forums and on the server, you stand more of a chance of becoming Trusted than that of a communitally inactive person. Also, make sure to use correct punctuation, grammar, and of course, spelling, as the community likes this and will tend to respect those players who use correct English than those who don't.
The third aspect is quite simply if you have ever been banned, kicked, or even warned before. If you have had any of this occur to you, then the chances of becoming a Trusted member can go down quite severely, of course depending on what you did. Basically, do NOT grief, be kind and respectful to ALL players, and every now and then give stuff away at spawn to new players. Operators see this, and they take this into consideration.
The fourth aspect is to keep quiet about this matter. Do NOT badger the Operators regarding if they Trust you or not, as in more chances than not their opinion of you will have dropped at that moment. Just keep quiet, don't talk about it to ANYONE (Unless, of course, they are your friend, and you tell them via /msg) as I know myself that people who ask this question are often quite annoying. My friend in-game had to learn this the hard way. Both me and another one of his friends got Trusted when he didn't.
I hope I have helped you here, so please take my advice seriously as it will help you get your way into Trusted. Please note that this does NOT guarantee a position, but it will help.